It is well known that achieving a fluid-tight seal is vital in a wide variety of situations. In the surgical environment, particularly in connection with surgical procedures requiring percutaneous entry into a vessel of a patient to remove stenotic blockages or plaque in an artery or other vessel of a patient, preventing fluid loss or leakage is essential. Whether in surgical or other environments, the permutations of problems associated with preventing fluid leakage are numerous.
Several examples occur in the field of atherectomy surgery. Atherectomy surgery was developed to avoid the problems of conventional bypass surgical procedures. Conventional bypass surgical techniques are extremely invasive. Atherectomy surgery is much less invasive. Atherectomy surgical techniques employ small cutting tools attached to a catheter. The atherectomy device can be inserted into the vessel of a patient through a less invasive incision in the patient, an incision not located near the heart. The cutting tool may be advanced until contact is made with a stenotic blockage in the vessel. When positioned at the stenosis, the cutting tool may be activated from outside the incision to cut away stenotic blockages. Atherectomy procedures, while extremely beneficial, have inherent fluid leakage problems.
One significant leakage problem results from the need to activate the catheter to rotate the cutting tool through the stenosis to remove the blockage. The catheter, typically inserted into the vessel of a patient through an introducer sheath, may extend a considerable distance from the distal tip of the cutting tool to the proximal end of the catheter, the proximal end being engaged with a device for rotating the catheter. Depending on the velocity of rotation of the catheter, the catheter may rotate both concentrically and eccentrically around the longitudinal axis of the catheter. A seal is needed to insure that fluids from the vessel of the patient do not leak from the introducer sheath during concentric and eccentric rotation of the catheter during a surgical routine.
Another of the leakage problems associated with atherectomy surgery arises from the need to change catheters during a surgical procedure. It may be necessary to change catheters and the cutting tool attached to the catheter. The problem to be solved is to remove the catheter from the vessel of the patient without inducing leakage through the introducer sheath. The concomitant problem is to be able to reinsert the atherectomy device through the introducer sheath without causing leakage from the vessel of the patient.
An additional potential leakage problem arises because of the cutting tool itself. As indicated, it may be necessary to insert and remove the catheter and cutting tool frequently during an atherectomy surgical procedure. Frequent contact between the blades of the cutting tool and a conventional introducer sheath seal ultimately will reduce effectiveness of the conventional seal. The solution is to provide a device for avoiding contact between the seal and the cutting tool during insertion and removal of the catheter.
Yet another related problem arises in connection with insertion of the cutting tool through an introducer sheath. The cutting tool itself could be dulled or damaged because of resistive pressure applied against the cutting tool by the seal during insertion of the catheter. Resiliency of the seal is not the solution. A seal which is too resilient may compromise the primary purpose of the seal, to prevent fluid leakage. The solution is to provide a device which permits insertion and removal of the cutting tool while avoiding contact between the cutting tool and the seal.
In light of the above, it is an object of the present invention to provide a device for introducing a rotatable atherectomy catheter into an artery of a patient. Another object of the present invention is to provide a seal which prevents fluid leakage during operation of a rotating catheter in the artery of a patient. Yet another object of the present invention is to provide a device for preventing leakage from the vessel of a patient during insertion and removal of a catheter during an atherectomy surgical process. An additional object of the present invention is to provide a device which precludes damage to the seal and to the cutting tool during insertion and removal of the catheter. Still another object of the present invention is to provide a device for introducing a rotatable atherectomy catheter into an artery of a patient which is easy to operate, is relatively easy to manufacture, and is comparatively cost effective.